There is an increasing interest in glucanases in the food and feed industries. These enzymes find application for instance in the fruit juice industry for liquefaction of plant cell wall material (pending application EP 94202442.3). They may also serve as processing aids to reduce fouling of membranes. In the feed industry the role of .beta.-glucanases in reducing the viscosity of various sorts of grains is well established. Many of the enzyme preparations used in the food and feed area are derived from Aspergillus species, usually Aspergillus niger. This is a safe host which produces a large variety of enzymes such as pectinases and hemicellulases with characteristics which make them suitable for applications at moderate temperatures and at neutral to acidic pH. In contrast to pectinases and hemicellulases, cellulases are usually derived from Trichoderma. Trichoderma species such as reesei, viride or longibrachiatum are good producers of cellulolytic enzymes. However, Trichoderma enzymes cannot be used everywhere due to regulatory constraints. Thus, it would be of considerable economic value to have a good source of Aspergillus enzymes. However, up till now, it has not been possible to clone the genes encoding glucanases from A. niger using the traditional method involving enzyme purification, partial amino acid sequencing and isolation of the gene or cDNA for the enzyme of interest by the derived DNA sequence.